1. Field of the Invention
The present invention relates to a manual transmission for vehicles, in which any one of a plurality of forward shift stages and a reverse shift stage can, selectively, be established by movement of a shift member operatively associated with the selecting and shifting operations of a change lever, an engage portion provided on a restraining member which is connected to a drive means for moving the restraining member from an inoperative position to an operative position during forward travelling of the vehicle, and the shift member is restrained from moving to a position in which the reverse shift stage is established by the abutment of the shift member against the engage portion.
2. Description of the Related Art
There is known a conventional manual transmission capable of selectively establishing any one of a plurality of forward shift stages and a reverse shift stage, wherein the movement of a shift member for establishing a reverse shift stage is restrained by a restraining member in order to prevent the accidental or inadvertent shifting to the reverse shift stage during forward travelling of a vehicle (for example, see Japanese Patent Application Laid-Open Nos. 25555/89 and 65753/90).
In the manual transmission described in the above-described Japanese Patent Application Laid-Open No. 25555/89, if the vehicle speed exceeds a predetermined speed, a solenoid is energized to protrude the restraining member, so that the restraining member restrains the shift member from moving in a direction to establish the reverse shift stage. However, such restraining member consists of the output shaft of the solenoid and, hence, a load from the shift member acts directly on the solenoid and may worsen the durability of the solenoid.
In the manual transmission described in the above-described Japanese Patent Application Laid-Open No. 5753/90, a hydraulic pressure developed in accordance with an increase in vehicle speed causes a cylinder to be operated, so that a restraining member, consisting of a piston slidably received in the cylinder, is brought into engagement in a groove provided in the shift member. Even in this case, however, a load from the shift member acts directly on the piston, which may worsen the durability of the piston.
Any of the above prior art transmissions is accompanied by a problem that if a trouble happens in the solenoid or a hydraulic system by the load, or the like, received from the shift member, causing the restraining member to stick at an operative position, the movement of the shift member is restrained by the restraining member, resulting in an inability of shifting to the reverse shift stage.